The time for necrosis to occur after a fracture of the femoral neck is uncertain and is related to a variety of factors, such as the fracture site, the patient’s physical fundamentals, and so on. It needs to be affected according to the individual’s physical condition, nutritional condition and post-care situation, generally within five years after the onset of necrosis of the femoral head may lead to necrosis of the femoral head. 1. Physical condition of the individual: the femoral head itself has poor blood circulation, after the fracture of the femoral neck, the local blood circulation will be damaged, and the nutrients can not be delivered to the fracture site, thus causing necrosis of the femoral head. 2. Nutritional situation: after fracture, the body needs to supplement sufficient protein and calcium, which can make the fracture site recover better, if the nutrition can not be supplemented in time, it may also lead to necrosis. Therefore, after the fracture, you should replenish the nutrition in time, you can eat chicken, fish and other foods rich in nutrition. 3. Post-care: If the fracture is inactive for a long time, the bacteria in the fracture site will breed and cause infection, which may also lead to necrosis, so the fracture site should be kept clean and hygienic. Fracture of the neck of the femur needs timely treatment and care, so as not to delay the condition, or even lead to serious consequences.